Injector nozzle



Jan. 3, 1939.

N. DRAPER INJECTOR NOZZLE 'Filed Feb. 3, 1938 2 Sheets-Sheet l In venior0 15a] ,izzz ver A iiomeus Jan. 3, 1 939.

N. DRAPER INJECTOR NOZZLE Filed Feb. 3, 1938 2 Sheds-Sheet 2 Inventor 7L2-1Z Ira 0 92 By My 5mm A tiorneys Patented Jan. 3, 1939 UNITED STATES2,142.97: mmc'ron NOZZLE Neal Draper, Albuquerque, N. Men. assignor ofone-half to J. W. Gaskill, Albuquerque, N. Mex.

Application February a, 1938, Serial No. 188,570 3 Claims. (01.ass-101.2)

My invention relates to improvements in iniector nozzles for Diesel typeengines.

By way of explanation, it is well known that the Diesel type engine isstill undesirable as an automobile power plant principally because ofvarying combustion efliciency and consequent variations inworkingpressure, or power, developed. This is' due primarily to the factthat the spring loaded needle valve type of fuel injectors with whichsuch engines are equipped vary in operation under different fuel pumpspeeds and to an extent resulting in. varying spray velocities .andfrequently chattering of the valve with consequent' pulsations in thefeed of fuel. Another 1.) factor contributing to varying an ineflicientcombustion in such engines is that pump pressures in present day systemsof fuel injection are relied upon solely to effect atomization of thefuel and such pressures are insufficient to effect complete vaporizationessential to proper combustion in such engines.

Having the foregoing in mind, it is the principal object of my inventionto provide an injector nozzle for Diesel type engines constructed foroperation under control of energy obtained from pressure in thecombustion chamber of the en gine, thereby obviating the abovedisadvantages incident to varying pump speeds and utilizing the higherpressures obtainable in said chamber to obtain perfect vaporization ofthe fuel.

Other and subordinate objects are also comprehended by my invention allof which, together with the precise nature of my improvements, will bereadily understood when the succeediag description and claims are readwith reference to the {drawings accompanying and forming part of thisspecification. In said drawings: I Figure 1 is a view in side elevationof my improved injector nozzle,

v Figure 2 is a view in longitudinal vertical section, showing the partsin normal position,

Figure 3 is a view partly in side elevation and partly in longitudinalsection illustrating the operation of the nozzle, I

Figure 4 is a fragmentary view similar to Figure 3 further illustratingthe operation of the nozzle,

Figure 5 is a view in vertical transverse section .u taken on the line5-5 of Figure 2 looking in the direction indicated by the arrows.

Figure 6 is a view in perspective of the valve stem and valve the latterdetached from the former, and

Figure '1 is a view in vertical transverse section taken on the line ofFigure 2 looking in the direction indicated by the arrows.

Referring to the drawings by numerals, the basic element of my improvednozzle is a tubular casing comprising a pair of relatively small and 5large front and rear sections I and 2, the latter having a closed rearend 3, an axially outwardly extending threaded nipple l at the rear endthereof, and a radially extending threaded nipple 5 adjacent said rearend all for a purpose present- 10 1y seen.

The front section I is threaded at its rear end, as at I. into the frontend of the rear section 2 and provided with an external radial flange Iadapted to bear against the front end of the rear 15 section 2, and aninternal similar flange 8 intermediate the flange and the rear end ofsaid section. The front end of the section I is ground to provide aninternal conical valve seat 0 extending around said end. 20

Slidably mounted in the section I, in front of the flange 8, is a shortpiston it having an inwardly tapering front end forming a similarlyshaped chamber ll therein, and a rear axial bore forming a rear chamber[2 therein, a central 26 axially bored abutment wall It intermediatesaid chambers, and a small tubular axial plunger ll extending forwardlyfrom the wall It and piston III and terminating in an enlarged circularhead I! having a flat .front face I 8 and a cylindrical periphery l1.Slidably mounted in the plunger l4, and wall It, is a tubular valve stemll having an enlarged circular rear end I! looselyfltting in the chamberl2, 9. closed front end 20. and a disk like valve 2| fixed on saidclosed end 20 concentrically thereof as by a hub 22 on said valve and 'apin 23 passing through said end and hub. The valve has a bevelled inneredge 2| ground to flt the seat 9, and a flat bottomed, circular chamber25 in its inner face concentric-thereto and 40 into which the head I! ofthe plunger II is designed to flt with the outer face thereof flatagainst the bottom of the chamber. The valve stem i8 is bored axiallyfrom its inner end, as at 2t, and provided in the chamber 25 withlateral Q5 discharge ports 21 leading from the bore 28 into saidchamber. 4

Extending from the rear end of the piston ll, axially thereof and of thesection 2, into the latter, is a tubular stem 2! having an enlargedfront 50 end 29 threaded into the chamber l2 and closing the rear endthereof and having fast on its rear end a circular follower Ill betweenwhich and the flange I a tension spring 3| is interposed in surroundingrelation tothe stem 28, said spring urgu ing the follower l0, stem 2',piston II, and plunger i4 rearwardly.

Suitably secured in the rear end of the stem 2. is one end of a tubularfuel feed line 22 extending slidably through the nipple l and havingcoils 31 formed therein between the stem 28 and the rear end of thesection 2. A gland nut 34 threaded onto the nipple t with packing 35therein forms a seal around said line for a purpose presently clear.

Referring now to the use and operation of the described invention, thenoLzle is mounted in the usual manner in the engine with the valve 24 inthe compression chamber of the latter, the nipple I is suitablyconnected to a hydraulic pump, and the fuel feed line 32 is suitablyconnected to a source of fuel supply under pressure.

In the normal position of the parts the stem 2|, piston ll, plunger i4,and valve ii are retracted by the spring 3i with the piston il in aposition such that a chamber it is previded in the front end of thesection I. In this position of the piston II the valve 2i is seatedagainst the seat I and held thereagainst by engagement of the wall llwith the end I! of the valve stem is. The head I! of the plunger I4 iswithdrawn from the chamber 26 of the valve 2| suficiently to just clearthe edge of said chamber.

Before the compression stroke of the engine begins a metered quantity offuel is passed into the chamber 25 by way of the fuel line 32, stem 2|,chamber l2, valve stem I8 and ports 21. As the engine piston nearlyreaches the top of the compression stroke hydraulic pressure isintroduced into the section 2 by way of the nipple 5 and by actionagainst the piston i0 causes the valve 2i to suddenly move off the seat9 into opening position. In the meantime and prior to such opening ofthe valve 2| the head it of the plunger it has been driven into thechamber 25 thereby compressing the fuel in said chamber and ejecting thesame around said head in the form of spray into the chamber 36. Thesudden opening of the valve allows the highly compressed air in thecombustion chamber to rush into the chamber 36 past the valve seat 9.This air rushing past the valve seat 9 picks up the fuel which is beingsprayed out of the chamber 25, by the action of the plunger I4, andthoroughly atomizes the fuel. The rush of air into the chamber 38 causesa pressure wave within the chamber beginning at the valve seat andreaching to the back of the chamber i I, the pressure becoming greaterand greater due to the impact of the air particles upon each other asthey are suddenly stopped in chamber ii where the pressure andtemperature become so high that the fuel particles are instantlyignited. The pressure rises even higher after combustion begins, alsothe pressure wave reverses. The result is a surge of the fuel mixturetoward the open end of the section i.

The hydraulic pressure in the section 2 is now interrupted whereupon theparts are returned to normal position partially under action of thespring 2i and partially under action of pressure within the combustionchamber, said pressure acting to seat the valve 2i and force the plungerll, piston ill and stem 28 into retracted position until the valve isseated at which point the spring ll completes the retraction of saidplunger, piston and stem. At this point it should be explained thatduring forward movement of the piston Iii and plunger H the valve 2| ispicked up by the plunger head I! after the fuel has been ejected fromthe chamber 25 by said head, in the mander previously described, andopened in opposition to pressure exerted thereagainst by compression inthe combustion chamber of the engine.

The invention will, it is believed, be clearly understood from theforegoing without further explanation.

Manifestly the invention, as described, is susceptible of modificationwithout departing from the inventive concept and right is hereinreserved to all such modifications falling within the scope of thesubjoined claims.

What I claim is;-

1. In an injector nozzle of the class described, a cylindrical casinghaving a closed rear end and a circular seat in the front end thereof, acylindrical pist-on dividing the casing into front and rear compartmentsand having a closed front end and a chambered rear end, a tubularplunger integral with the piston and extending forwardly and axiallythereof, a valve stem slidably mounted in the plunger with its endsextending therefrom and having an enlarged rear end loosely fitting inthe piston chamber and an axial bore therein opening into the pistonchamber and terminating adjacent the front end of the stem in lateraldischarge ports, a disk valve fast on the front end of the stem adaptedfor cooperation with the seat to close the front end of the casing andhaving a chambered inner face fitting around the front end of the pistonplunger, means to introduce fluid into the rear compartment of theeasing from a source of supply under pressure, means to tension thepiston against forward movement, and means to admit fuel through therear end or the casing into the piston chamber.

2. In an injector nozzle of the class described, a cylindrical casinghaving a closed rear end and a circular seat in the front end thereof, acylindrical piston dividing the casing into front and rear compartmentsand having a closed front end and a chambered rear end, a tubularplunger integral with the piston and extending forwardly and axiallythereof, a valve stem slidably mounted in the plunger with its endsextending therefrom and having an enlarged rear end loosely fitting inthe piston chamber and an axial bore therein opening into the pistonchamber and terminating adjacent the front end of the stem in lateraldischarge ports, a disk valve fast on the front end of the stem adaptedfor cooperation with the seat to close the front end of the casing andhaving a chambered inner face fitting around the front end of the pistonplunger, means to introduce fluid into the rear compartment of thecasing from a source of supply under pressure, means to tension thepiston against forward movement, and means to admit fuel through therear end of the casing into the piston chamber, including a tubular fuelconducting stem threaded into the rear end of the piston, and a pipeline extending from said stem through said rear end and slidabletherein.

3. In an injector nozzle of the class described, a cylindrical casinghaving a closed rear end and a circular seat in the front end thereof, acylindrical piston dividing the casing into front and rear compartmentsand having a closed front end and a chambered rear end, a tubularplunger integral with the piston and extending forwardly and axiallythereof, a valve stem slldably mounted I in the plunger with its endsextending therefrom and having an enlarged rear end loosely fitting inthe piston chamber, and an axial bore therein opening into said pistonchamber and terminating adjacent the front end of the stem in lateraldischarge ports, a disk valve fast on the front end of the stem adaptedfor cooperation with the seat to close the front end of the casing andhaving a chambered inner face fitting around the front end of theplunger and into which said ports discharge, means to introduce fluidinto the rear compartment of the casing from a source of supply underpressure, means to admit fuel to the rear end of the easing into thepiston chamber in- 10 eluding a tubular fuel conducting stem threadedinto the rear end of the piston, and a pipe line extending from saidstem through said rear end and slidable therein, and means to tensionthe piston against forward movement including a follower on the rear endof the fuel conducting stem, a flange in the casing, and a tensionspring surrounding said-fuel conducting stem and interposed between thefollower and flange.

